1. Field of the Invention
This invention relates to an improved retractable syringe having a cannula which after use may be drawn into the barrel portion of the syringe, and, more particularly, a syringe for the hypodermic administration of drugs and other medicinal preparations which, after use, may be discarded. The problem of contact by personnel with contaminated implements is thereby avoided.
2. Information Disclosure Statement
With the advent of the acquired immune deficiency syndrome (AIDS) and the prior problems in health service organizations controlling hepatitis, an improvement in syringe technology is indicated. While prior art has shown a retractable cannula structure several technical problems still remain. Becuase of the medical personnel using syringes, the retractability feature must of necessity be simple, easy to operate, and highly reliable. Furthermore, the present technology has not disclosed a cannula and hub assembly which is mounted retractably within the cylindrical body of the syringe.
In preparation for this application, a pre-examination patentability search was performed in Class 604, subclasses 110 and 195. The search uncovered U.S. Pat. No. 4,026,287 of Irene Haller (originally classified in Class 128/215 and cross-referenced into Class 128/218P). In contradistinction to the application at hand, Haller '287 teaches a frangible structure which structure approaches disposal in a manner readily distinguishable from that which follows.